1. Field of the Invention
This invention relates to implements or apparatus for applying a pushing or pulling force having special engaging elements and an impact delivery component. More specifically, this invention relates to a tool for extracting the remnants of square sheared signposts and a method for using the same.
2. Background of the Invention
Proper signage and illumination is critical to road safety. Small roadway signs and luminaries are often mounted to square steel or aluminum posts. For safety reasons and to protect the occupants of out-of-control vehicles that may strike these posts, they are equipped with splices or breakaways that fail upon impact with the vehicle. The steel often used in the manufacture of sign posts is typically re-rolled rail steel or new billet steel conforming to the mechanical standards of ASTM A 499, Grade 420 and to the chemical requirements of ASTM A 1. One example is 80 ksi Marion™ steel having a weight of between three and four pounds per foot. The sign posts are typically punched along their centre lines. The punch holes are about 11 mm in diameter and are spaced at either 25 mm or 75 mm centers. The posts are generally galvanized according to ASTM A 123. The signposts are generally mounted in cement or concrete having specified standards such as Class “A” Portland™ cement. There are many other state and national standards and regulations, such as those promulgated by the Federal Highway Administration, the ATTSA, MUTCD and the AASHTO, that apply to such posts and breakaway standards but all generally demand high standards of safety and durability.
Once a steel post has been struck by a vehicle, the breakaway device permits the shear failure of the bottom portion of the post while retaining the post foundation in the ground. Within the post foundation, a remnant of the post often remains stuck and mutilated. Since the post has been struck with great force, the remnant is often very difficult to remove. In many cases, the remnant cannot be removed using available tools and therefore the entire post foundation may have to be excavated in order to install a new post. This creates additional expense for municipalities in terms of material and manpower required to excavate and reinstall a new sign post. Therefore, while breakaway devices are mandatory for public safety they can create costly maintenance disadvantages.
Known post-pulling devices such as the “T” Post Puller-Pounder described in U.S. Pat. No. 5,042,591 issued to Hull on Aug. 27, 1991 do not solve the problem of pulling remnants from sheared sign posts. The Hull device is too heavy to be easily used by a single person and is not adaptable to the problem described above.
Therefore, what is needed is a simple hand-operated device that can be used to extract the remnants of square sign posts from their anchors permitting the re-use of foundations and the easy re-installation of new sign posts. Such a device would significantly reduce the labour and cost required to perform this task and therefore is clearly desirable.